High pressure delivery system

ABSTRACT

This relates to an improved delivery system for accurately loading and controlling the delivery of flowable material to a patient. Particularly, the system may be used in the injection of hard tissue implant materials such as PMMA under pressures up to about 4000 psi. The system includes an applicator with a first column having an implant material introduction section adapted to provide for effective loading of the implant material and a second column housing a piston. The introduction section has a larger size than that of a vessel section or bore in which the requisite pressure seal between the piston and bore wall is formed. The first column may include an introduction section flared open to an included larger funnel-like opening or a separate funnel may be used that interfaces with the introduction section to facilitate the introduction of implant material. Handles on the first and second columns to be turned relative to each other to advance the columns toward each other may be provided for manual actuation of the applicator to drive implant material through a cannula and deliver implant material to a desired site.

TECHNICAL FIELD

The present invention relates to a system for more accuratelycontrolling the delivery of flowable material to a patient.Particularly, the system may be used in the injection of hard tissueimplant materials. Features of the invention provide for effectiveloading of an applicator configured to generate high fluid deliverypressures.

BACKGROUND OF THE INVENTION

The introduction of flowable material to an implantation site within apatient to effect one or more therapeutic goals is well known. Theflowable material itself may be of high or low viscosity. Matter rangingfrom typical fluids or solutions to non-Newtonian fluids, pastes, gelsand the like has been used for one purpose or another in the medicalarts.

It is well-recognized that syringes may be used for percutaneousdelivery or injection of flowable material. However, such devices are oflimited value in the delivery of high viscosity fluids. In general,users are only capable of generating pressures of about 100-150 psi with10 cc syringes. This places a limitation on the viscosity of theflowable material that can be effectively “pushed through” the syringeand attached needle or cannula and fully delivered to a treatment site.The use of a small barrel syringe, e.g., a 1 cc syringe enables the userto generate higher driving pressures (e.g., pressures of 800 psi andpossibly as high as 1000-1200 psi) that may be used to flow a viscousimplant material. However, the 1 cc volume of the syringe may be verylimiting as to the amount of material deliverable to a patient. This canbe especially problematic when the material to be injected is a settablecomposition where (for various reasons) it is important to deliver allthe material desired in a single “shot”. Another problem with a 1 ccsyringe is lack of control, as high pressures are generated in a“spike-like” response time and are not continuously controllable.

Other devices used in the medical arts do not suffer such a controlproblem by virtue of a threaded arrangement used to advance a pistonhead within a bore to drive material from a loaded device. U.S. Pat. No.29,083 to Irving discloses a syringe having a plunger with a screwthread on its exterior. Advancing the plunger by turning it relative toa housing generates sufficient pressure to force a semi-solid ointmentout of a perforated tube. This applicator, however, is only configuredfor rectal delivery of a hemorrhoid medicament.

By contrast, U.S. patent application Ser. No. 09/053,108, entitled“Pressure Applicator for Hard Tissue Implant Material,” by Preissman,filed Apr. 1, 1998 and U.S. Pat. No. 6,383,190, entitled “High PressureApplicator,” by Preissman, filed on even date herewith, eachincorporated by reference herein as part of the invention, disclose highpressure applicators utilizing two threaded columns in variousarrangements capable of use for injecting material in useful procedures.

While the applicator of the earlier-filed patent application byPreissman does not provide some of the advantages of the presentinvention (particularly in loading implant material), the applicatorsdisclosed in each patent application are of practical utility ashigh-pressure applicators for use in percutaneous vertebroplasty. Inthis procedure, once a cannula is positioned in the cancellous bone of avertebrae, a hard tissue implant material such as Polymethylmethacrylate(PMMA) is injected into a site for treatment to reinforce and solidifythe damaged hard tissue.

Generally, about 3.5 cc of implant material per side of the vertebralbody is required. Control issues aside, this makes the use of a 1 ccsyringe problematic. Basically, a vertebroplasty procedure would requiremultiple reloading steps with such a syringe. Further, the additionaltime spent for such action would result in more than mere inefficiency.Reloading time is time spent while an implant material like PMMA ispolymerizing to become increasingly viscous beyond a state in which itmay be safely or effectively delivered by any type of injection device,regardless of its high-pressure capacity. Both the need to inject theimplant material through a relatively narrow needle or cannula and thefact that the desired site is relatively closed (i.e., trabecular bone)compounds material thickening effects which make “single shot” deliveryability important.

While PMMA in a nearly-solidified state is inappropriate for use withthe present invention, a highly-viscous or syrupy consistency of PMMA isgenerally believed to be most advantageous for performing percutaneousvertebroplasty. Such a consistency insures that the implant materialstays in place much better than a less viscous, more flowable material.

It is known that leakage or seepage of PMMA from a vertebral implantsite or extravasation through fractures in the bone can cause a host ofcomplications—some of which can be very serious and even result indeath. For example, Weil et al. reported cases of sciatica anddifficulty in swallowing which were related to focal cement leakage,Radiology 1996; Vol. 199, No. 1, 241-247. A leak toward the distal veinsposes an even more serious risk, since this can cause a pulmonaryembolism which is often fatal.

In addition to leakage around the cannula and through bone, overfillingof the intended implant site can result in introduction of implantmaterial into the blood stream after removal of the cannula from theimplant site. Due to the high pressures involved in the implantprocedure, compliance within the delivery system can act as acapacitance under pressure thereby storing a volume of the implantmaterial and energy under pressure which, upon release of the pressure,drives an undesired additional amount of implant material into theimplant site to cause potentially-dangerous overfilling. This additionalamount of outflow is sometimes referred to as “oozing” or “drip”. Systemcompliance may also result in decreased response performance of thedelivery system.

Compliance may be introduced into a system either by virtue ofappreciable elasticity of tubing, by other members forming part of thedelivery system or by air bubbles introduced in the filling or loadingof the applicator with implant material. Purging of air from a systemloaded with highly-viscous matter may be difficult or impossibleespecially where air bubbles are not initially only near the system'soutlet. This is because air bubbles will simply not be able to buoy to apoint where they may be ejected without extruding a large volume of theimplant material intended for implantation from the applicator.

Specific adaptation for venting or purging of air from a syringe fordelivering viscous material is disclosed in U.S. Pat. No. 4,795,444 toHasegawa et al. In this device, space is provided in a top section ofthe syringe so that an end of a plunger may pass through material in thetop section to vent air bubbles before forming a seal in the smallerdiameter bottom section of the syringe. The differential in sizes of thesections may be provided in stepwise fashion, as a tapered wall or as bya recessed channel. All this being said, as stated previously—a syringeis of limited utility or practicality as a high pressure applicator andcannot be effectively used as an applicator in the present invention dueto various shortcomings inherent to the limitations of syringes asdiscussed above.

Accordingly, especially for use with PMMA in percutaneous vertebroplastyprocedures, there exists a need for an improved system able to providesubstantially non-complaint and precise application of implant materialunder high pressures to a desired location in a single batch. The systemof the present invention includes method and apparatus adapted to meetsuch needs as well as provide other advantages readily apparent to thosewith skill in the art.

SUMMARY OF THE INVENTION

The present invention is an improved system for controlled delivery ofinjectable material to a patient. It includes a first column including avessel section open to an implant material introduction section. Asecond column is provided which is drivably engageable with the firstcolumn along an advancement axis. Handles may be provided on the firstand second columns for manual actuation of the device by turning thecolumns relative to each other where a threaded interface is provided. Apiston or plunger member is provided and advances within the vesselsection of the first column upon advancement of the second column togenerate pressure to drive implant material loaded within the vesselsection. Although a close-tolerance or slight interference fit betweenthe piston and the vessel section may be provided to develop a seal, itis preferable to provide an O-ring or other sealing element as typicallydone in the art.

The introduction section of the first column has a slightly largercross-sectional area than that of the portion of the vessel sectionadjacent to it. Providing a larger size or diameter introduction sectionthan vessel section entrance enables the introduction of the piston intothe implant material without simultaneously forming a seal wherecompliant bubbles may be trapped. Put another way, the differential insizes is provided so that when the vessel section is fully filled andthe introduction section is at least partially filled, the end of thepiston may be dipped in the implant material to allow for the exclusionof air bubbles prior to driving it into the vessel section.

Where the implant material is less viscous, the piston may merely beplunged in to implant material in the introduction section and driveninto the vessel section. Where the implant material is more viscous, itmay be advisable to more carefully place the piston in contact with theimplant material in the introduction section to avoid air bubbles (byturning, rocking or otherwise manipulating the piston) and theninserting it into the vessel section where a seal is formed.

The introduction section of applicator in the present invention may berelatively close in size to the vessel section entrance to provide onlya surrounding dam for a meniscus poured over the vessel section. Sincethe amount of material to be provided in the introduction section neednot be great to facilitate the venting or purging as described above, inusing the invention it is better to only introduce slightly more implantmaterial than will fill the vessel. Introduction of a larger amount ofimplant material is not only wasteful, but may result in materialdrainage out of the introduction section into other parts of theapplicator—especially when the applicator is inverted or turned as willoften be the case in preparing PMMA implant material for delivery.

To help account for the possibility of excess implant material andassociated potential of fouling of the applicator by such excess, alarger size of the introduction section than strictly required for theventing feature discussed above may be used to act as a catch basin forimplant material. This will provide an increased margin of error inpouring implant material into the applicator before overflowing theintroduction section. Further, the walls of such an enlarged catch basinmay help to prevent contamination of the applicator by virtue ofadherence of the implant material to the surface area provided duringinversion or agitation of the applicator.

The present invention may include a funnel or increased-size targetregion integrated into the first column, adjacent to the introductionsection, to aid in pouring implant material into the applicator. Drivethreads may be placed on the exterior of the funnel section. However,when no integral funnel is provided, drive threads may be placedexterior to the introduction section which may be of a finer pitch orhigher thread count than those on a larger diameter. A smaller diameterand/or finer threads will provide for greater mechanical advantage forgenerating higher driving pressures more easily. To help in loadingmaterial into the applicator when no integral funnel is used, a separatefunnel element may be provided to interface with the introductionsection.

The present invention includes such features of the pressure applicatordiscussed above as well as the methods involved in preparing and usingthe applicator to inject material into a patient. Such methods orprocedures involve preparing an applicator by at least partially fillingan introduction section with a material for delivery above a level atwhich a piston may form a seal and driving a piston head into a vesselsection bore where a seal is formed without the introduction ofcompliant matter such as air bubbles. The preparation method may befollowed by introducing material from the applicator into a patient in amedical procedure that may be distinct and separate from the inventivepreparation method.

The invention also includes those concomitant parts or elements useablewith the applicator in delivering material to a site within a patient.Such elements may include a delivery hose, a cannula (alone or incombination with one or more stylets) and vertebroplasty implantmaterial. Reference is made to preferred embodiments of these elementswhich are described in further detail below. Together, these elementsmay form part of the inventive kit or system to be used in a procedureor method as variously described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Each of the following figures diagrammatically illustrates aspects ofthe present invention. No aspect shown is intended to be limited to theexpression pictured.

FIG. 1 shows the primary components of the inventive flowable implantmaterial delivery system and indicates the manner in which they areassembled.

FIG. 2 shows the implant delivery components assembled and prepared foruse.

FIG. 3 show the cannula and two types of stylets useable in theinvention and indicates the manner in which they are assembled.

FIGS. 4A and 4B show views of the ends of a hose and connectors useablein the invention.

FIG. 5 shows a first column including an integrated funnel section.

FIG. 6 shows alternate first columns and an independent funnel useablewith each.

FIGS. 7A, 7B and 7C show views of a housing member, retainer member andplunger.

DETAILED DESCRIPTION OF THE INVENTION

An example procedure for using precision instruments according to thepresent invention in an intravertebral vertebroplasty will now bedescribed. It is expressly noted, however, that this invention isuseable in a myriad of other procedures where virtually any flowablematerial to be delivered to a patient under pressure is employed. Butfor percutaneous vertebroplasty, initially a surgeon identifies alandmark with the aid of fluoroscopy or other imaging technique. Next,an injection is given to anesthetize the skin where insertion willoccur. A long needle, having a length sufficient to percutaneouslyaccess the periosteum of the target vertebra is then used to injectanesthesia subperiostially.

After sufficient time has passed to effectively anestheitize the skin,an incision is made through the skin with a scalpel. A combined styletand cannula 2 (such as stylet 4 and cannula 6 threaded together, asshown in FIG. 1) and further described in U.S application Ser. No.09/409,984, “Precision Instruments For Use In Vertebroplasty” byPreissman et al., filed on even date herewith and “Precision DepthGuided Instruments for Use In Vertebroplasty” filed Oct. 14, 1997,incorporated by reference, are then inserted through the incision andadvanced using a translation motion with not torquing, until the tip 8of the sytlet abuts the cortical bone of the vertebra or the periosteumsurrounding it. Once contact has been made, the cunnula tube is thengrasped with a pair of hemostats and fluoroscopy/imaging is used toassess the position of the cannula/stylet with regard to the vertebra.The hemostats are used to allow the hands of the user to remove from thefield in which the imaging radiation will be applied. With the aid ofmedical imaging, the cannula/stylet 2 are positioned with respect to thepedicle of the vertebra at the desired orientation for passing therethrough and into the body of the vertebra. Imaging may be performed bothperpendicular to the longitudinal axis of the spine/vertebra, as well asalong the longitudinal axis of the cannula/stylet, or at an angle to thelongitudinal axis of the cannula stylet.

If the advancement of the stylet and cannula does not proceed along theintended pathway, the stylet 4 may be reverse rotated while preventingrotation of the cannula 6 to maintain it in position and remove thestylet. A second stylet 10, as shown in FIG. 3, which has an asymmetrictip 12 may then be inserted into the cannula and connected therewith.Stylet 10 is configured essentially identically to stylet 4 with theexception of the distal end thereof. Rather than a pointed and threadedtip portion, stylet 10 is provided with a beveled tip portion 12. Apreferred angle of orientation of the beveled surface is about 30° withrespect to the longitudinal axis of the stylet, although this angle maybe varied to include any acute angle to give various responses indirectional steering of the stylet 10.

Yet another stylet may be included which as other double-beveled ordiamond-shape tip portion adapted to pass through the cannula. Stillfurther, stylets having conical or pyramidal type tip portions having asubstantially smooth surface may be additionally or alternativelyprovided. All of these stylets may be useful for improved “targeting”ability in initially piercing skin or hard tissue. Other uses,advantages and a more detailed description of variations of each of thesytlets advantageously useable in the present system are described in“Precision Depth Guided Instruments for Use in Vertebroplasty,” U.S.patent application Ser. No. 09/409,948, filed on even date herewith,which is herein incorporated by references, especially as to thatdisclosure. The operator can rotate the sytlet 10 to position the tip 12in a direction toward which he/she wishes to migrate the stylet 10. Oncethe orientation of the stylet 10 and cannula 6, having been advancedover the stylet 10, has been satisfactorily set, the fluoroscopy/imagingis discontinued, the hemostats are removed and the operator carefullygrasps the cannula/stylet being careful not to alter the orientation.Stylet 10 with the beveled tip 12 is then removed and replaced by stylet4 with self-tapping threads 8. Grasping the combination handle 14, andoptionally the cannula tube 16, the operator then proceeds to both pushtranslationally and the torque the combination handle to begin threadingthe stylet 4 into the cortical bone.

After “biting” into the bone with a few turns of the self-tappingthreads 8, the operator's hands are removed and the devices maintaintheir position by the support provided by the bone surrounding thethreads. The devices/instruments are again viewed fluoroscopically orotherwise imaged both along the longitudinal axis of the cannula/styletand laterally to determined the depth of the instruments. If the desireddepth and placement has not yet been achieved, imaging is discontinued,and the cannula/stylet are further torqued or otherwise advanced intothe cancellous bone until the tip of the cannula has been positioned ina desirable location.

Upon achieving the desired placement of the cannula at a site fortreatment, the operator reverse rotates the stylet 4 to remove it fromthe cannula 6, while preventing rotation of the cannula 6. The cannulaat this stage is effectively press-fit into the bone site which aids theoperator in preventing its rotation. Once the stylet has been completelyremoved from the cannula, fluoroscopic imaging/viewing of the cannulamay optionally be performed to assure that the cannula did not moveduring the removal of the stylet.

Optionally, a contrast agent, e.g. a product known as OMNIPAQUE 300available from Nycomed in Princeton, N.J., may be injected through thecannula and the flow of the contrast agent is viewed fluoroscopically orwith other imaging in order to ascertain that the tip of the cannula hasnot been placed in a vein or other significant vessel. Preferably thecontrast agent is injected through tubing connected to the cannula. Whentubing is used, it is preferably of a smaller length and diameter thantubing that is used for injection of implant material. Contrast agentmust be flushed out of the vertebra prior to injection of theimplantation material, so it is preferable to inject a small volume ofthe contrast agent. Viewing of the flow of the contrast agent helps toidentify the shape of the vertebral body into which the injection ofimplant material is to be performed, as well as to locate where themajor veins lie. After completing the flow of the contrast agent, theremnants of the contrast agent are flushed out of the vertebral body byinjecting a flushing solution (e.g., saline) through the cannula 6,using a syringe or other injector. The imaging is preferablydiscontinued for this step. It is preferable to use a minimum amount ofcontrast agent. The contrast agent is flushed out so that it does notocclude, cloud, or otherwise compete with the viewing of the radiopacityof the implant material when it is placed.

The cannula 6 at this point will be filled with saline. If not filled bysaline by such flushing, then it may be backfilled. The substantiallynon-compliant conduit 18, is used, may be connected to the pressureapplicator 20 and have implant material forced through it prior to beingattached to the cannula 6. An example of an implant material forvertebroplasty is a PMMA bone cement containing contrast agentsincluding radiographic powder or particles of any typical material suchas U.S.P. Barium Sulfate and/or tracer particles. Aspects of acceptableimplant material are described in U.S. Pat. No. 6,019,776, “EnhancedVisibility Materials For Implantation In Hard Tissue” by Preissman,filed Oct. 14, 1997.

Luer fitting/locks 22 may be used to provide a high pressure capacityconnection between the respective members of the inventive system. Adetailed description of a high pressure, noncompliant conduit or tubing18 which can be used in this invention is give in the copending commonlyassigned U.S. patent application Ser. No. 09/276,062, “Non-Compliantsystem For Delivery Of Implant Material” by Preissman, filed Mar. 24,1999, which is hereby incorporated by references thereto, in itsentirety.

Non-compliance of the system is further achieved by loading of theapplicator 20 to avoid the introduction of air bubbles as contemplatedby the present invention. Such loading is provided for by means ofplunger head 26 smaller in size than an introduction section 24 so itmay freely pass through the introduction section as it is introducedinto a vessel section 28 where a frictional seal may be formed. In theembodiment of the invention shown in the figures, round members are usedfor the piston head 26, vessel section 28 and the introduction section24 of first column 30. It is noted, however, that any advantageousgeometry may be used for the vessel section 28. It is preferable that atleast a portion of the first column 30 be round though, since threads 32may then be placed on its exterior to engage with mating threads 34(FIG. 7A) on the interior of second column 36.

Where a different manner of drivably engaging first column 30 relativeto the second column 36 is desired (e.g., a ratcheting interface, or apneumatic or hydraulic driven arrangement) a round shape of theintroduction section 24 may be less preferred. Other drive mechanisms orembodiments of interest which may be used in the present invention arealso discussed in U.S. Pat. No. 6,019,776, entitled “Precision DepthGuided Instruments For Use In Vertebroplasty,” filed Oct. 14, 1997, U.S.Pat. No. 6,033,411, entitled “Precision Depth Guided Instruments For UseIn Vertebroplasty,” filed Oct. 14, 1997, and U.S. patent applicationSer. No. 09/409,984, entitled “Precision Depth Guided Instruments ForUse In Vertebroplasty,” filed on even date herewith, each by Preissmanand herein incorporated by reference in their entireties.

Where the first column 30 and second column 36 are configured forthreaded engagement to be driven towards or away from each other, it isadvantageous to provide handles 38 and 40 on the columns. The handlesmay be integrally formed or merely affixed in some matter. Preferably,handle 40 on the first column 30 is in the form of a radially-extendingarm. This may serve as a stabilizer when a knob-like grip 38 is turned.Such actuation of the applicator 20 will avoid twisting the conduit 18or cannula 6 during the delivery of material.

Where threads are used or torsional movement is translated into axialmovement of the columns 30 and 36 toward each other otherwise, it willbe advantageous to provide an enlarged base 44 b of the piston/plungerrod 44 with an end 44 d having a spherical surface which is free torotate with respect to the inner end surface 36 d of the second column36. The enlarged base 44 b is held in position by the placement of oneor more (preferably two) internal retaining rings 42 which engage withina recess in second column 36 and abut the enlarged base 44 b tosubstantially prevent translational movement thereof with respect to thesecond column 36. Thus the rod 44 will not fall out of the second column36 when inverted or otherwise jostled, but the rod 44 is still allowedto turn relative to the column 36.

Such turning relative to the housing 36 will be advantageous especiallywhen using gritty implant material to help preserve seal 50 since it maymerely translate within the pressure vessel 28 rather than rotatethrough its translation. The retaining member 42 may comprise one ormore star-shaped internal retainers, for example, as shown in FIG. 7B,or the like.

The various portions of the pressure applicator 20 may be sized toprovide sufficient mechanical advantage to enable the application ofpressures up to about 4000 psi by hand. As alluded to variously,mechanical advantage of the system is determined in large part by handlesize 38, 40, the bore size or the vessel section 28, and the mechanicaladvantage of the drive means. In the embodiments shown, threadings areprovided on the exterior of the first column 30 and interior of thesecond column 36. Manufacturing and material considerations, and thediameter on which to place the threads will determine the thread pitchwhich may be used. This in turn determines the mechanical advantage ofthe drive means. Where a greater mechanical advantage is desired, afiner thread pitch will provide the same. Also, the diameter of threadedsections of the columns 30 and 36 may be decreased. Alternately, a finerpitch thread may be used on a relatively larger diameter section bychanging material or manufacturing procedure (such as cutting thethreads into the respective members rather than molding the pieces as ispresently preferred). In all, a pressure applicator produced accordingto the present invention is a balancing of various design goals relatingto performance and cost.

In the embodiment pictured in FIGS. 1, 2 and 5, the introduction sectionis flared open to an integral target or funnel section 52 between about1 and 1.75 inches in diameter to facilitate pouring implant materialinto the first column 30. The inclusion of an integral funnel section 52makes for an elegant, multi-functional receptacle member. However, dueto the threadings which may be molded in such large diameter columns 30and 36, the mechanical advantage which may be generated by virtue ofuseable thread pitches is not the most powerful possible.

Where a greater mechanical advantage is desired, the inventive pressureapplicator 20 may be configured like the embodiments shown in FIG. 6. Ineach, the introduction section 24 is only slightly larger than the boreof the vessel section 28 and piston head 26 or seal 50. In theembodiments of FIG. 6 where the introduction section does not include anintegral funnel section, the introduction section 24 can be sized about0.010 to about 0.250 inches over that of the vessel section bore. Theintroduction section is preferably between about 0.5 in to about 1 inchin height, but may be effective at heights as small as half thethickness of an O-ring being inserted therein, e.g., 0.031 inches. Thisvalue, in particular, is driven by the distance of the sealing portionof the plunger 44. For instance, if an O-ring is provided at the veryend of the plunger or piston, then the introduction section need only beas high as roughly half the O-ring thickness. The O-ring thickness ispreferably about 0.062″.

Aside from what provisions may be made for threading or other drivemeans/mechanism, the shape of the first column 30 exterior to theintroduction section 24 is variable. As shown in FIG. 6, the exteriordiameter of the first column member may be substantiallyconstant—excepting optimal threads provided. Alternatively, the diameterof the exterior of the first column 30 may follow that of the interiorso a substantially constant wall thickness “T_(w)” is employed. Thelength of threading provided may be varied.

In the pictured embodiments of the invention, the pressure vesselsection 28 is advantageously about 0.375 to about 0.75 and preferablyabout 0.50 inches in diameter in order to have a small enough bore sothat the mechanical advantage in applying pressure to the implantmaterial is not overly affected as would be the case with a much largerbore in view of other design parameters. A length for the vessel isbetween about 1.5 and 3.5 inches so to hold a volume of material betweenabout 4 cc and above 9 cc.

As illustrated in FIG. 6, the embodiments not having an integral funnelsection 52 may be used in combination with a separate funnel 54. Wherean independent funnel section is used, it may be preferred to use aneven larger opening than that of the integrated funnel 52. Funnels withopenings of up to about 3 inches would prove useful. Such sizing isreasonable for separate funnels because the exterior of the funnel willnot require threadings to interface with a housing member, andconsequently, workable size will not be limited by drive meansparameters as with the embodiment shown in FIGS. 1, 2 and 5. Departurefrom a cylindrical profile for an introduction funnel may beadvantageous in any embodiment where there will be no threads on theexterior of the funnel.

In embodiments of the invention, it is preferable that the funnelsection employed have radiused corners or none at all. A funnel height“H_(f)” of between about 1 and about 4 inches is preferable whether thefunnel is integrated into the first column 30 or not. It is preferredthat the introduction section have a height “H_(i)” of between about 1.5and about 2 times over the increase in diameter from the vessel sectionbore to the introduction section. It is further preferred that implantmaterial to be loaded in the applicator 20 be filled to a level withinthe range of “H_(i)” to facilitate the purging or venting function ofthe invention. Filling proceeds to a desired fill level 56 shown in FIG.2.

Preferable material for the applicator 20 including the first column 30,second column 36 and independent funnel 54 when provided is amorphousnylon. Clear amorphous nylon is preferred for the first column 30 andfunnel 52 or 54. The material of the second column 30 may be polished orfrosted to the desired fill level 56 to aid in filling with the properamount of implant material by visual observation of the material.Graduated level marks 58 may also be provided so a quantitativeappreciation of the amount of material in the first column 30 may beobserved. Of course, alternate material may be useable for the pressureapplicator 20 of the invention. Such material includes stainless steel,aluminum or titanium and their alloys, and polymers including, but notlimited to, polypropylene and polyvinylchloride (PVC).

To load the applicator 20 of the invention, implant material 46 ispoured to or over the desired fill level 56 which is at least part wayinto the introduction section 24 of the first column 30. The head 26 ofthe piston or plunger member 44 is then dipped into the implant materialwhere air and excess material flows past the same because of the spaceprovided between the piston head 26 and introduction section 24 walls.Upon further advancement of the piston 44 into the first column 30, aseal is formed with the vessel section wall 60.

Use of a second column 36 like that shown in FIG. 7A is advantageous inhelping provide for such action. A thread-bare section 64 is providedhere by which threading 32 on the first column 30 may pass thoroughwithout interference. Sliding the threaded section 32 into section 64not only facilitates dipping the plunger head 26 into material in theintroduction section 24 but it aligns the threads 32 and 34 so they maystart evenly and avoid becoming “cross threaded.” Even where asingle-start thread is employed in the invention, the alignment providedby the interaction between section 64 and the first column 30 will beuseful in this regard. The bare section 64 is preferably of a lengthsuch that a number of threads will be engaged with each other before aseal is formed between the piston 44 or seal 50 and the vessel wall 60.

To form the seal, a separate “sealing” element need not be provided.However, especially where highly viscous materials are concerned, theO-ring or grommet optionally provided is preferred since it can move onthe plunger rotationally and thus even if the plunger is turning withthe handle, the seal can move independently.

Upon loading of the applicator 20, preferably be inverting it andallowing it to rest on a flat top portion 62, some amount of materialmay be extruded from the device in order to purge air in the Luer lock22 or hose 18. The flat configuration of handle 38 also provide a restupon which the device may be self supported, after filling and threadingthe device together. It may also be desired to agitate the applicator tokeep particles in the implant material evenly dispersed. Since anoverabundance of flowable implant material provided in the introductionsection during loading will be unconstrained and may foul the exposedthreads of the second column 36 upon inversion of the applicator, it ispreferable to only fill the introduction section with such an amount ofmaterial as required to effectively vent or purge air bubbles asdescribed above.

Following proper loading of the device and such post-loading proceduresas may be advantageous for a given implant material, delivery of thematerial to a patient may commence by urging the second column 36 towardthe first column 30 and thus the piston 44 into the pressure vessel 28to force implant material therefrom. In the embodiments shown, suchmovement will be provided by torque applied by a user to turn thehandles 38, 40 relative to each other. Where other drive means areprovided (as may be routinely substituted by those with skill in theart), the action required to advance the plunger 44 within the firstcolumn will vary but the device and method of use will still beconsidered to be part of the present invention. Fluoroscopic or otherimaging may be used continuously or intermittently during the deliveryof the implant material into a patient to monitor the progress of thefilling of an implantation site.

Various end-point indicators may be used to indicate that driving ofimplant material should be discontinued and that the filling procedurehas been completed. The particular end point indication method useddepends upon a variety of factors, including the characterization of thevenous bed within the particular vertebral body being filled, thecondition of the bony structure of the vertebral body being filled, andsurgeon preference. One end-pointing technique is to simply monitor thefilling and terminate driving of the implant material when visualconfirmation is made that the body is completely, or nearly-completelyfilled.

Another end point indicator (which is not necessarily selected by theoperator, but is event driven) is when implant material extravasatesoutside of the vertebral body. This condition may arise due to escape ofthe implant material through fracture lines, such as when the vertebralbody is that of an osteoporitic patient who has suffered a compressionfracture. When end pointing is prompted by such an event, thenon-compliant aspects of the invention facilitated by effective loadingof the device will lessen or eliminate “oozing” or “drip” phenomenonthat could result in overfilling the implantation site and theassociated dangers.

After filling of the vertebral body has been completed as indicated byone of the endpoint detection indicators described above or others,including those described in U.S. patent application Ser. No. 09/409,984referenced above, any remaining pressure is relieve by unthreading thecolumns ½ to a full turn. The tube 18 is disconnected from the cannula6, and the cannula is withdrawn. A bandage is typically then applied tothe wound site.

Further details as to the use or other aspects of the high-pressureimplant system may be noted in the above referenced applications alreadyreferred to in describing the present invention or background which areherein incorporated by reference in their entirety. It is noted thatthis invention has been described and specific examples of the inventionhave been portrayed. The use of those specific examples is not intendedto limit the invention in any way. Additionally, to the extent thatthere are variations of the invention which are within the spirit of thedisclosure and yet are equivalent to the inventions found in the claims,it is the intent that the claims cover those variations as well. Allequivalents are considered to be within the scope of the claimedinvention, even those which may have not been set forth herein merelyfor the sake of brevity. Also, the various aspects of the inventiondescribed herein may be modified and/or used in combination with suchother aspects also described to be part of the invention or disclosed inreferences discussed to form other advantageous variations considered tobe part of the invention covered.

We claim as our invention:
 1. A high pressure application for drivingthe delivery of a flowable tissue implant material comprising: a firstcolumn including a vessel section and an introduction section, saidvessel section defining a substantially smooth bore having an outlet andan entrance adjoining said introduction section, said introductionsection defining an opening having a larger cross-sectional area thansaid bore; a second column drivably engageable with said first columnalong an advancement axis; and outside said first column; and a pistonmember having a base and head, wherein said head is adapted to form ahigh-pressure seal in said bore and said base is positioned against aportion of said second column.
 2. The applicator of claim 1 wherein saidbore is cylindrical.
 3. The applicator of claim 2 wherein at least aportion of said opening of said introduction section has a circularcross-section perpendicular to said advancement axis.
 4. The applicatorof claim 3 wherein said driveable engagement comprises a threadedinterface on an outer portion of said first column and an inner portionof said second column.
 5. The applicator of claim 1 wherein a handle isprovided for said second column.
 6. The applicator of claim 5 whereinsaid handle is in the form of a scalloped member at an end of saidsecond column.
 7. The applicator of claim 1 wherein a handle is providedfor said first column.
 8. The applicator of claim 7 wherein said handleis in the form of a member extending substantially perpendicular to saiddriving axis at an end of said first column.
 9. The applicator of claim1 wherein said piston head is sized for a close fit with said bore. 10.The applicator of claim 1 wherein said piston head has a groove and anO-ring configured to form a seal in said bore.
 11. The applicator ofclaim 10 wherein said O-ring comprises PTFE/TEFLON.
 12. A kit comprisingthe applicator of claim 1 in combination with tissue implant material.13. The kit of claim 12 wherein said implant material comprises PMMA.14. The applicator of claim 1 wherein said outlet exhausts though a Luerfitting.
 15. The applicator of claim 14 wherein said Luer fitting isintegrally formed in said first column.
 16. The applicator of claim 15wherein said first column comprises clear amorphous nylon.
 17. Theapplicator of claim 16 wherein said second column comprises amorphousnylon.
 18. The applicator of claim 1 wherein said base of said pistonmember is frictionally engaged with said second column by a restraintadapted to allow said piston member to turn during operation of theapplicator.
 19. The applicator of claim 4 wherein a smooth transitionsection connects said bore and said introduction section.
 20. Theapplicator of claim 4 further comprising an integrated funnel sectionadjacent to said introduction section, said funnel section having anopening with a diameter between about 1 and about 2 inches.
 21. Theapplicator of claim 20 wherein said funnel section has a height betweenabout 0.25 and about 1.75 inches.
 22. The applicator of claim 4 whereinsaid introduction section has a diameter between about 0.010 to about0.25 greater than a diameter of said vessel opening.
 23. The applicatorof claim 22 wherein said introduction section has a height between about0.1 and about 0.5 inches.
 24. The applicator of claim 23 in combinationwith an independent funnel member adapted to interface with saidintroduction section.
 25. The applicator of claim 1 wherein it isadapted to generate about 4000 psi with tissue implant material by handactuation.
 26. A high pressure applicator for driving the delivery of aflowable tissue implant material comprising: a first column including avessel section and an introduction section, said vessel section defininga substantially smooth bore having an outlet and an entrance open tosaid introduction sections, said introduction section being flared openfor at least one portion; a second column drivably engageable with saidfirst column along an advancement axis; and outside said first column;and a piston member including a base and head, wherein said head isadapted to form a high-pressure seal in said bore and said base inpositioned against a portion of said second column.
 27. The applicatorof claim 1, further comprising an integrated funnel section adjacent tosaid introduction section, said funnel section having an opening with adiameter of about 1 inch or greater, a high pressure application fordriving the delivery of a flowable tissue implant material comprising: afirst column including a vessel section and an introduction section,said vessel section defining a substantially smooth bore having anoutlet and an entrance adjoining said introduction section, saidintroduction section defining an opening having a larger cross-sectionalarea than said bore wherein said introduction section opening is atleast about 1 inch in diameter; a second column drivably engageable withsaid first column along an advancement axis; and outside said firstcolumn; and a piston member having a base and head, wherein said head isadapted to form a high-pressure seal in said bore and said base inpositioned against a portion of said second column.
 28. The applicatorof claim 27, wherein said diameter is up to about 2 inches.
 29. A highpressure applicator for driving the delivery of a flowable tissueimplant material to effect vertebroplasty comprising: a first columnincluding a vessels section having a volume of at least about 4 cc andan introduction section, said vessel section defining a substantiallysmooth bore having an outlet and an entrance adjoining said introductionsections, said introduction section defining an opening having a largercross-sectional area than said bore; a second column drivably engageablewith said first column along an advancement axis; and a piston memberhaving a base and head, wherein said head is adapted to from ahigh-pressure seal in said bore and said base is positioned against aportion of said second column.